Compressor for refrigerating apparatus



Feb. 25, 1941. K H 2,233,082

COMPRESSOR FOR REFRIGERATING APPARATUS Filed Aug. 28, 1936 3 Sheets-Sheet 1 I! z INVENTihA MM. KKIM ATTORNEY I Feb. 25, 1M1. KUQHER 2,233,082

COIIPRESSOR FOR R FRIGERATING APPARATUS s Sheets-Sheet 2 Fi1 ed Aug. 28, 1936 INVENTOR Md AT] ORNEY Patented Feb. 25, 1941 UNITED STATES COMPRESSOR FOR REFRIGERATING APPARATUS Andrew A. Kucher, Dayton, Ohio Application August 28, 1936, Serial No. 98,360

14 Claims.

The present invention relates to rotary compressors and the associated driving motors therefor and particularly to compressors of the vane type.

to provide a construction in which the vane or vanes of the compressor extend through the shaft or rotor and provides sealing bearing surfaces for a vane or vanes throughout the diame- 10 ter of the shaft whereby relatively long sealing and bearing surfaces for the vane or vanes may be provided within a small diameter shaft.

Another object is to provide a construction in which the rotor of the compressor and its in- 5 tegral drive shaft can be of the same diameter. Another object is to utilize the weight of the compressor rotor, and its driving mechanism for maintaining a seal between the rotor and the end of the cylinder.

A further object is to provide apparatus for and a method of maintaining a higher pressure substantially at all times at the sealing surfaces between the vanes and cylinder than is present I in the high pressure side of the cylinder, so as 25 to prevent the escape of fluid from the high to the low pressure sides of the vanes.

A still further object is to utilize the fluid compressed as a motive power for causing the vanes to be forced into sealing engagement with the 30 cylinder.

Still another object is to utilize oil under pressure to lubricate the vane bearings, and for caus' ing this oil to be directed adjacent the leading edges of the vanes whereby this oil is utilized as 5 a seal between the vanes and the cylinder.

To carry out the preceding object, it is a fur ther object to provide the rotor of the compressor with a pair of interfitting and overlapping vanes, which when expanded, form a conduit 40 therebetween through which high pressure oil is allowed to pass, the pressure of the oil tending to press the vanes against the cylinder walls, the

oil also seeping through the bearing between the interfitting portions of the vanes and leaks into 45 the cylinder adjacent to the leading edge of the rotating vane thus aiding in sealing the vane to the cylinder wall.

Other and further objects and advantages will be apparent from the following description, refer- 5 ence being had to the accompanying drawings wherein preferred forms of embodiments of the present invention are clearly shown.

Fig. l is a view of a longitudinal section taken through the center'of a motor and compressor '55 unit. r

One of the objects ofthe present invention is Fig. 2 is a view, on a larger scale, of one form of a rotary compressor detached from the motor; I I

Fig. 3 is a sectional view of the compressor taken on the line 3--3 of Fig. 2;

Fig. 4 is a sectional view of the motor shaft taken on the line 44 of Fig. 3;

Fig. 5 is a side view of the compressor shown in Fig. 2; i

. Fig. dis a perspective view, on a larger scale, of the interfltting vanes used in the compressor shown in Fig.2;

Fig. 7 is a fragmentary view of a compressor showing the cylinder and another type of vane construction, and,

Fig. 8 is a fragmentary view of a compressor having an elliptical bore and utilizing but a single vane.

A sealed motor compressor unit is shown in cross section in Fig. 1 wherein a motor 22 and a 20 depended compressor 24 are resiliently mounted within a casing 26 by a plurality of springs 28 and 30. The springs 28 arepreferably evenly disposed around the outer periphery of the motor 22 and between the motor 22 and the casing 26. A single, centrally located spring 30 supports the motor compressor and spaces it from the casing 26 at the bottom thereof. A detailed description of thistype of mounting construction may be obtained by referring to my copending 30 application ,8. N. 95,091.

Electrical connections for the motor 22 are preferably made by a suitable conduit 32 which is connected to the threaded inner end 33 of a binding post 34 by a loclmut 36. The outer end 38 of the binding post 34 is threaded, and is provided with two nuts 40 for the external electrical connections. The post 34 passes through an insulating bushing 42, made in several parts for ease of assembly, which is held within a metallic o bushing 44 that passes through, and is attached to the casing 26.

An inlet connection or low pressure tube 46 passes through the casing 26 at thelower end thereof and is connected to the compressor 24. 5 For example, the tube carries low pressure refrigerant and forms a return line for the refrigerating system (not shown) to the low pressure side of the rotary compressor 24. The tube 46 is welded to the casing 26 to assure a hermetic 5o connection between the two members. The compressor, during 'operation,fdischarges the compressed refrigerant directly into the closed casing 26 and high pressure refrigerant leaves the casing by a discharge or high pressure tube 43.

This tube 48 passes through the casing 26 at the upper end thereof and is welded or otherwise suitably secured to the casing 26. Thus the entire system, including the rotary compressor and its driving motor, is self contained into hermetically sealed casing 26.

The motorcompressor unitary assembly includes a motor frame 49 which carries a motor stator 58. A shaft 5| is journalled in a bearing 52 and carries the motor rotor 53 on its upper end. The shaft 5| extends through the bottom wall of the motor frame 49 and is utilized as a compressor rotor 54. A cylinder 55 having a bore 56 is disposed eccentrically with respect to the compressor rotor 54 and is secured in position by clam-ping the same between the bottom of the frame 49 and a plate 51 by bolts 58. The shaft 5|, including the rotor 54, is preferably the same diameter as the rotor, thus reducing the cost of manufacture. The bottom of the shaft 5| rests upon the plate 51 and, due to the weight of the shaft and motor rotor, it is in sealing engagement therewith.

The rotor 54 and cylinder 55 are disposed so that the periphery of the rotor 54 is tangent to the larger diameter of the cylinder throughout the length of the cylinder as indicated at 60, thereby forming a sealing surface between the rotor and the cylinder.

The rotor-54 is provided with a longitudinal slot 62 cut through it, which slot 62 extends from the bottom of the rotor 54 to a height equal the height of the cylinder 55. In one form, a pair of identical, interfitting and overlapping vanes 64 and 65 fit sufficiently snug within the slot 62 to form a seal therebetween and also to form a seal between the two vanes. The length of either vane 64 or 65 is such that at no time during rotation do both ends of the vane simultaneously touch the wall of the cylinder 55. Thus during rotation of the rotor 54, the vanes 64 and 65 are centrifugally expanded to form a hole between them at 66. This hole 66 is utilized as a conduit of an oiling system that is provided for the assembly.

An oil level is normally maintained within the casing 26, preferably to some point above the bottom of the compressor 24. Since high pressure refrigerant is within the casing 26 the oil, which is in the lower part of the casing 26, is under the same pressure as the high pressure refrigerant. This fact is utilized to provide high pressure lubrication for the system. To accomplish the desired result, a small hole 10 is drilled in the bottom plate 51 of the compressor 24. The hole 10 is drilled so that it registers with the hole 66 formed by the extension of the vanes 64 and 65. To carry the oil further, a longitudinal hole 12 is bored in the motor shaft 5|. The hole 12 is drilled coaxially with the shaft 5| and therefore registers with the other two holes 10 and 66. The upper end of hole 1-2 communicates with a transverse hole I4. The transverse hole I4 carries oil from-the longitudinal hole 12 to the periphery of the shaft 5|, whence the oil seeps between the shaft 5| and the elongated bearing 52. To increase the oil seepage, and to improve the lubrication of the bearing, an undercut I6 is provided intermediate the two ends of the bearing 52 and extends to about one half inch from either-end of the bearing, thus forming two extreme bearing surfaces 11 and 18. The 01] hole 14 is disposed to deliver oil directly to the upper bearing 11 and to the undercut 16. The undercut II, preferably does not exceed five one thousandths of an inch. The oil under pressure within the undercut I6 seeps in both directions to lubricate the bearings 11 and 78 as well as form an oil reservoir to assure adequate lubrication at all times.

An advantage of this type of lubricating system is that the oil under pressure within the bearing v52 tends to seep through the lower bearing portion 18 and tends topass into the cylinder 55 of the compressor. Thus oil under high pressure, except for very brief periods when the vane ends near an outlet or discharge port 84, is constantly tending to seep into the cylinder to prevent leakage of the fluid being compressed and thereby eflectively seals the vanes with the compressor walls. This same tendency toward oil seepage is occuring at the other end of the rotor, since oil is passing through the hole 10 in the bottom plate 51 and, being at a higher pressure, except for very brief periods when the vane ends near an outlet or discharge port 84, than the pressure within the cylinder, tends to seep into the cylinder and aids in sealing and lubricating the vanes at the lower ends thereof. From the foregoing it will be noted that all of the sealing surfaces of the vanes have high pressure fluid on one side thereof substantially at all times, the fluid being at a pressure nearly equal to the discharge pressureof the compressor. This film of oil at the sealing surfaces under high pressure increases the efficiency of the compressor since it aids in preventing the loss of gas at the sealing surfaces.

The compressor, 24 is provided with an inlet port or low pressure intake 80 which enters the cylinder 55 through a wall thereof and which may be connected by a threaded fitting 82 to the low pressure line 46. An outlet or discharge port 84 also disposed in the wall of the cylinder 55, allows the compressed refrigerant to escape from the cylinder 55. The discharge port 84 is normlly closed by a flapper valve 86 which consists of a leaf spring 88 suitably depressed at 98 to close the port 84. The spring 88 is set within a milled slot 92, in the compressor body 94, which slot lessens the length of the port 84 and provides a flat surface for attaching the spring 88 to the body 94. A machine screw 96, threaded into the body 94, holds the spring 88 in position at its fixed end, opposite the port 84.

The vanes 64 and 65, due to their slidable fit in the rotor 54, move reciprocally through the rotor slot 62 to. accommodate the portion of the cylinder 55 through which they are passing, for example, when the vanes are substantially vertical, with reference to Fig. 2, they protrude equal distances on either side of the rotor, but when they have moved 90 degrees, they protrude from one side only.

In operation, as the vanes 64 and 65 rotate with the rotor 54, they draw low pressure refrigerant into the cylinder 55 through the inlet port 80. As a vane passes the port 80 it causes a reduced pressure to be created behind the vane which draws the refrigerant into the cylinder 55. The other vane picks up this refrigerant, and due to the crescent shape of the effective cylinder, which decreases in volume as the vanes rotate, compresses the refrigerant, which compressed refrigerant is then exhausted or discharged through port 84 and by the valve 86. Thus the vanes 64 effectively divide the cylinder 55 into two progressively moving compartments, namely, a low pressure compartment and a high pressure compartment.

Since the casing 26 is under high pressure and vane to the cylinder.

due to the fact that oil is forced under high pressure through the lower part of the compressor at 10 and that oil is forced under high pressure through the undercut I6 and lower bearing I0, the top and bottom of the vanes are subjected to pressure from the exterior of the cylinder and thereby prevents leakage of fluid from the high to the low pressure sides of vanes and out of the top and bottom of the cylinder through the sealing surfaces of the vanes.

The entire side of one wall of the slot 52 forms a bearing surface for one side of the vane 64. This also is true of the other side of the slot 62 and the other vane 05. The faces of each vane 6-4 and 65 bear upon the adjacent faces of the other vane. Thus in effect, by this construction 04 and 05 leaks out into the cylinder between the interfi-tting leg I00 of the vanes 04 and 65. This may be explained by the fact that the oil in the hole. 66 is under greater pressure, practically at all times, than the internal pressure of the cylinder, because the oil is under the pressure of the discharge from the cylinder. The oil that leaks out from between the vanes is held in a pocket in front of the rotating, leading edge of th vanes 64 and 65. This aids materially in sealing the The oil pressure between the vanes '64 and 65, which aids the seal between the vanes as it tends to constantly urge the vanes toward the walls of the slot 62 as well as urge the vanes 64 and 05 and tends to constantly maintain this oil seal in front of the leading edge of the rotating vanes, is one of the distinct features of my invention. a

Another embodiment of my invention is shown in Fig. '7, where the only change is in the vane construction. A pair of identical vanes I02 is provided which is held in the slot 62 by two identical shims I04 disposed on either side of the vanes. These shims I04 and vanes I02 aresubstituted for the interfitting vanes 64 and 65 of the compressor shown in Fig. 2. These shims are sufficiently rigid, so as to maintain the vanes longitudinally aligned with the slot 02. Due to the sliding movement of the shims I04, during rotation of the rotor 54, long bearing surfaces are maintained at all times between the vanes and the shims and between the shims and th rotor. The shims I04 also provide for a constant length of seal between the vanes and the rotor slot 62. The vanes I02 are maintained in the expanded position by centrifugal force and by the pressure of the oil passing through the space I06 between the vanes I02. Here again oil seepage between the shims I04 and the vanes I02 provides an oil film at the leading edge of the rotating vanes to aid in sealing the vanes to the cylinder wall.

In the embodiment in Fig. 8, the bore H0 is made elliptical, so that a cross plane through the cylinder H2 is an ellipse with its major axis, the vertical axis, with reference to Fig. 8. A single vane III is provided, the overall length of which 'is equal to the length of the minor axis of the at both ends of the vane during rotation of the vane. The vane III thus divides the cylinder into two compartments. Here again the bearing surfaces for the vane are approximately equal to the diameter of the rotor and the sealing surfaces are therefore also approximately equal to the diameter of the rotor. A hole H6 is drilled through the vane M4 to allow oil to flow therethrough, the oil coming from the casing 26 through the hole 10 in the bottom plate of the compressor 24 and passing through the hole IIG into the communicating hole I2 in the motor shaft.

In all of the embodiments described the rotor 54 with its slot 62 is placed in the same relative position within the cylinder.- In all embodiments. the oil conduits I0 in the plate 51, the conduits 'in the vanes and the oil hole 12 always register regardless of the position of the rotor. Undercuts I'II may be provided in the opposite ends of the vanes 84, 65, I02 and Ill for this purpose.

Among the advantages of my present invention is the reduction in size of the compressor with an attendant reduction in loss due to friction whereby an eflicient and low cost compressor is provided. By extending the vane or vanes completely through the slot in the rotor, substantial size bearing surfaces are maintained whereby th turning torque on the vane, during rotation, has substantially no detrimental effect, the long bearing surfaces for the vanes, maintaining the vanes in strict alignment with the slot at all times. By providing long bearing surfaces in this manner, the rotor has been reduced in size. Likewise the cylinder and other parts of the compressor can be made smaller. Since a small rotor can be employed, .the friction losses between the end of the rotor and between the ends of vanes and the cylinder end walls are materially reduced. Although the rotor has been reduced in size, nevertheless, a long sealing surface is maintained between the compartmentsof the cylinder, that is, by extending the bearing surfaces completely through the rotor and :by having the vane or vanes in contact with the bearing surface throughout the length thereof, an effective seal is maintained at these sliding joints.

While the forms of embodiments of the present invention as herein disclosed constitute preferred forms, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow:

I claim:

1. In a rotary compressor, in combination, a cylinder, a bearing, a shaft journalled in the bearing, said shafts being less in diameter than the diameter of the cylinder, and extending into the cylinder, said shaft having uniform diameter within the bearing and cylinder and bearing tangentially against and in sealing engagement with cylinder, end walls for said cylinder, a rotor of less diameter than that of the cylinder, said rotor having a driving extension uniform in diameter with the rotor in the cylinder and extending through one of the end walls, said rotor bearing tangentially against and in sealingengagement with a side wall of the cylinder, the end of the rotor within the cylinder sealingly engaging the other end wall of the cylinder.

3. In a rotary compressor, in combination, a cylinder, 9, bearing, a shaft journalled in the bearing and extending into the cylinder, said shaft being less in diameter than the diameter of the cylinder, said shaft having uniform diameter within the bearing and cylinder and bearing tangentially against and in sealing engagement with a wall of th'e'cylinder, and vane means within the cylinder extending through the shaft.

4. In combination, a casing containing lubricant; a compressor including a cylinder having an end face, said end face having an oil passage extending therethrough for conducting lubricant from the casing, a rotor disposed eccentrically within the cylinder and having a longitudinal slot, vane means within the slot and forming the entire inside wall of a conduit, said conduit being in constant communication with the oil passage in the end face; a shaft bearing; a shaft for the rotor journalled in the bearing and disposed exteriorly of the cylinder and having an extending oil hole in constant communication with the conduit for conducting lubricant to the bearing.

5. In combination, a casing containing lubricant; a compressor including a cylinder having an end face, a rotor disposed eccentrically within the cylinder and having a longitudinal slot, vane means within the slot and forming the entire inside wall of a conduit; a shaft bearing; a driving shaft for the rotor extending exteriorly of the cylinder, said shaft having an oil hole leading to the bearing and said end face having an oil hole, said oil holes being constantly aligned with said conduit for conducting lubricant from the casing to the bearing.

6. In combination, a casing containing lubricant; a compressor including a vertically ex tending cylinder having a bottom end face, said end face having a vertically extending passage therethrough for conducting lubricant from the casing, a rotor disposed eccentrically within the cylinder and having a longitudinal slot, vane means within the slot and forming a conduit in constant communication with the oil passage in the end face; an upwardly extending bearing member; a shaft member for the rotor journalled in the bearing member, one of said members being undercut to provide a plurality of spaced bearing surfaces for the shaft member, said shaft member having an extending oil hole in continuous communication with the conduit for conducting lubricant to the upper bearing surface.

7. In combination, a casing containing a lubricant; a compressor including a vertically extending cylinder having a bottomend face, a rotor disposed eccentrically within the cylinder and having a longitudinal slot, vane means within the slot and forming a conduit; an upwardly extending bearing member; a shaft member for the rotor journalled in the bearing member, one of said members being undercut to provide a plurality of spaced bearing surfaces for the shaft member, said shaft member having an oil hole leading to the upper bearing surface and said end face having an oil hole, said oil holes being constantly aligned with said conduit for conducting lubricant from the casing to the bearing surfaces.

8 Compressing mechanism comprising in combination, means forming a cylinder, a rotor within the cylinder and having a longitudinal slot extending through the rotor substantially throughout the length of the cylinder, a plurality of overlapping vanes slidable within the slot, inner portions of said vanes being spaced from one another at. all times to form the entire inside wall of an oil conduit, said means having an opening leading from the high pressure side of the compressing mechanism and registering with the conduit for conducting oil to the conduit.

9. Compressing mechanism comprising in combination, a cylinder having an end face, a rotor within the cylinder and having a longitudinal slot extending through the rotor substantially throughout the length of the cylinder, a plurality of overlapping vanes slidable within the slot, inner portions of said vanes being spaced from one another at all times to form the entire inside wall of an oil conduit, said end plate having an opening leading from the high pressure side of the compressingi mechanism and registering with the conduit.

10. Compressing mechanism comprising in combination, means. forming a cylinder, a rotor within the cylinder and having a longitudinal slot extending through the rotor substantially throughout the length of the cylinder, a plurality of overlapping vanes slidable within the slot, inner portions of said vanes being spaced from one another at all times to form the entire inside wall of an oil conduit, said means having an opening leading from the high pressure side of the compressing mechanism and registering with the conduit for conducting oil to the conduit, a shaft for driving the rotor, a bearing for the shaft, said shaft having an oil hole registering with the conduit and extending to the bearing.

11. In combination, a casing containing lubricant; a compressor including a cylinder having an end face, said end face having an oil passage therethrough for conducting lubricant from the casing, a rotori disposed eccentrically within the cylinder and having a longitudinal slot, overlapping vanes within the slot, said vanes being undercut longitudinally and cooperating with one another to form the entire inside wall of a conduit, said conduit being in communication with the oil passage in the end face; a shaft hearing exterior of the cylinder; a shaft for the rotor journalled in the bearing and having an oil hole in communication with the conduit for conducting lubricant to the bearing.

12. In combination, a casing containing lubricant; a compressor including a cylinder having an end face, said end face having an oil passage therethrough for conducting lubricant from the casing, a rotor disposed eccentrically within the cylinder and having a longitudinal slot, overlapping vanes within the slot, one end of each vane engaging the cylindrical wall of the cylinder and one end of each vane being spaced from the cylinder wall, the cylinder engaging end of each vane trailing the adjacent end of the other vane, said vanes being undercut longitudinally and cooperating with one another to form the entire inside wall of a conduit, said conduit being in communication with the oil passage in the end face; a shaft 'bearing exterior of the cylinder; a shaft for the rotor journalled in the bearing and having an oil hole in communication with the conduit for conducting lubricant to the bearing.

13. In combination, a closed casing containing oil under high pressure; a rotary compressor including a cylinder having an end face, said end face having an oil passage therethrough for conducting lubricant from the casing, a member within the cylinder and bearing tangentially against the cylindrical wall of the cylinder, said side face of one of the vanes sealingly engaging substantially the entire surface of'one side of the slot and a side face of the other vane sealingly engaging substantially the entire surface of the other side of the slot, the opposite faces of the vanes being spaced throughout from the surfaces of the slot, said vanes being undercut longitudinally and cooperating with one another to form the entire inside wall of a conduit, said conduit registering with the oil passage in the end face.

14. In combination, a closed casing containing 011 under high pressure; a rotary compressor including a cylinder having an end face, said end face having an oil passage therethrough for conducting lubricant from the casing, a member within the cylinder and bearing tangentially against the cylindrical wall of the cylinder, said member having a longitudinal slot therethrough', a pair of overlapping vanes within the slot, a side face of one of the vanes sealingly engaging substantially the entire surface of one side of the slot and a side face of the other vane sealingly engaging substantially the entire surface of the other side of the slot, the opposite faces of the vanes engaging one another and each having surfaces in difierent planes extending in opposite directions and to the extreme opposite edges of the vane, the step portions in different planes of the vanes being spaced from one another to form a conduit, said conduit registering with the oil passage in the end face.

- ANDREW A. KUCHER. 

